The present invention generally relates to a comprehensive automatic directory assistance apparatus and, in particular, relates to such an apparatus that is subscriber accessed through a conventional telephone exchange and which receives, as an exclusive input thereto Dual Tone Multi-Frequency, (DTMF) signals and responds, as an exclusive output therefrom, via synthesized voice.
In an effort to reduce operating expenses, telephone communication system suppliers have, in recent times, devoted considerable effort toward developing automated directory assistance systems. The primary goal of such systems is to reduce the need for human operators or switchboard attendants while providing a wide range of services to the subscriber. Most of the present systems, nevertheless, either require at least an initial human response to the calling subscriber or provide limited services. For example, a call presently placed to directory assistance is answered by an operator who accepts the callers request for information and enters that information into a data terminal. The data terminal subsequently responds with the requested number via a voice synthesizing mechanism. There are other conventional caller assistance systems which are located between the callers telephone and the central switching exchange to intercept a call and provide, for example, automatic call routing. Such intercepting systems require that the caller know the number of the person he is calling; otherwise, the call must be passed through the central switching exchange to a human operator.
Still other automatic directory assistance systems require voice recognition by the system. One such system is described in U.S. Pat. No. 3,928,724, entitled "Voice Actuated Telephone Directory Assistance System" issued to Byram, et al. on Dec. 23, 1975. In the system described therein a caller must literally spell the complete last name of the party about whom he is requesting information. The system then provides the requested number by voice synthesis. In the event that more than one last name matching the spelled name exists in the directory, the caller is requested to spell the first name and, in the event of continued duplication the caller is requested to provide an address. Such a system has the drawback that it provides a very limited service and bidirectional dialogue is not possible. In addition, such a system would be difficult for anyone with a speech impediment, or an accent, to utilize. Hence, under such cirumstances, a caller would nevertheless need to be connected to a human operator. Another system requiring spelled vocal input is described in U.S. Pat. No. 4,164,025 issued to Debnowsky, et al. on Aug. 7, 1979.
There are, in addition, numerous systems available using many different types of data searching. These systems, however, require the intervention by an operator. Examples of such systems are described in U.S. Pat. No. 4,104,717 issued to Fujimura; U.S. Pat. No. 4,020,473 also issued to Fujimura; U.S. Pat. No. 3,529,295 issued to Brass, et al., and U.S. Pat. No. 3,242,407 issued to Hagelbarger, et al.
In addition to these more conventional systems, various limited electronic answering services are available, which answering services receive DTMF inputs and provides a callers name and number. Such devices are discussed in U.S. Pat. Nos. 4,117,542 and 4,304,968 issued to Klausner, et al. However, such systems are rather restrictive because of the limited memory available therewith and provide only specific information. Further, because of the limited memory in such devices, expansion into a larger system wherein a large volume of names having the same letters may be present would be quite difficult. Another drawback of such systems is that the input thereto frequently requires a codification of the persons name. That is, if the letter K were to be entered the user would need to depress the #5 keypad twice; the first depression indicating not only the location of the keypad but also the first of the group of letters (i.e. JKL) thereon, the second depression indicating the second position of the particular letter group of the three located thereon. Of course, to enter the letter L would require a third depression of the keypad. Such a system of input is subject to serious potential data entry errors and consequently results in considerable system inefficiency. In addition, such a system requires user training prior to the utilization of the service, i.e., it is not considered user friendly by present standards.
Other systems which provide other, but nevertheless rather limited services, other than telephone number identification, such as direct calling via name insertion, are also known. For example, U.S. Pat. No. 4,341,929 issued to Alexander, et al., describes a dedicated call-by-name system which, upon receiving a spelled name, directly connects the caller to the party whose name was spelled. However, such a system is designed for use by an operator using a full keyboard and hence, does not reduce the expense of providing directory assistance to any or all of the users of the system.
In addition to the above described systems, it is also generally known to provide message centers whereupon a subscriber call call in and, upon entering a specific code, receive messages left for him by other parties. One such system is described in U.S. Pat. No. 4,327,251 issued to Fomenko, et al. Such a message service is, of course, of limited use for a large group of subscribers.
From the above discussion, it is clear that there is a clear and considerable need for an apparatus that provides comprehensive directory assistance service to a subscriber, is easy to access and is ergonomically compatible with the expectation of a majority of users.